The present invention relates to a mobile lifter which comprises a plurality of inner tubes received in a cylindrical casing and sliding one inside another, a driving mechanism, and a winch controlled by the driving mechanism to take up or let off a cable so as to lift or lower the mobile lifter.
During the maintenance work of the outside wall of a building, a scaffold may be set up outside the wall or a suspension gear may be installed in the roof of the building or an aerial ladder may be used to carry the workmen to the desired elevation. These equipment are difficult to set up or expensive to install. There is also known a mobile lifter designed for carrying a workman for an overhead work. This structure of mobile lifter, as shown in FIG. 1, comprises a stand, a work table supported on the stand by a telescopic support, and a hydraulic cylinder mounted on the stand. When in use, the hydraulic cylinder is operated to pump a hydraulic oil into the telescopic support, causing the tube sections of the telescopic support to extend out of one another, and therefore the work table is lifted. This structure of mobile lifter is heavy and needs much working space. There is also known a similar mobile lifter which uses a pneumatic system controlled to lift or lower the tube sections of the telescopic support. However, this pneumatic system is dangerous in operation because an air leakage tends to happen during its operation.